"...described as 'Kupka's first attempt to come to terms with color theory in which the result is both personal and successful'. Although a self-portrait, the subject of the painting was the color yellow." Wiki "Although it is provocative to view The Yellow Scale as a self portrait, the true subject of this riveting work is the color yellow. The intense hues combine with Kupka’s confident gaze, a book in one hand, cigarette in the other, to convey a strong sense of the artist’s personality. Kupka was an eccentric, sensual man with a lifelong fascination for spiritualism and the occult. Though he never completely abandoned naturalistic representation, he was one of the pioneers in developing Abstract painting early in the 20th century. Kupka explored philosophically and scientifically the nature of color—its unity and total effect on a work of art. Beginning with one color, Kupka played out its full scale and range, which for him...." http://www.mfah.org/art/detail/yellow-scale/